Magnetoresistive memory device

Abstract

According to one embodiment, a magnetoresistive memory device includes a first magnetic layer in which a magnetization direction is variable, a first nonmagnetic layer provided on the first magnetic layer, a second magnetic layer provided on the first nonmagnetic layer, a magnetization direction of the second magnetic layer being invariable, and a second nonmagnetic layer provided on the first magnetic layer, which is opposite the first nonmagnetic layer. The first magnetic layer includes Mo.

What is claimed is: 
     
       1. A magnetoresistive memory device comprising:
 a first magnetic layer having a variable magnetization direction, the first magnetic layer including Mo; 
 a first nonmagnetic layer provided on the first magnetic layer; 
 a second magnetic layer provided on the first nonmagnetic layer, a magnetization direction of the second magnetic layer being invariable; and 
 a second nonmagnetic layer provided on the first magnetic layer, which is opposite the first nonmagnetic layer. 
 
     
     
       2. The device of  claim 1 , wherein:
 the first magnetic layer is a storage layer having magnetic anisotropy perpendicular to a film surface; 
 the second magnetic layer is a reference layer having magnetic anisotropy perpendicular to a film surface; and 
 the first nonmagnetic layer is a tunnel barrier layer through which a tunneling current flows. 
 
     
     
       3. The device of  claim 1 , wherein the first nonmagnetic layer comprises MgO. 
     
     
       4. The device of  claim 1 , wherein the first and the second nonmagnetic layers are different materials. 
     
     
       5. The device of  claim 1 , wherein the first magnetic layer includes Fe or Co. 
     
     
       6. The device of  claim 1 , wherein the first magnetic layer has a stacked layer structure in which a middle layer including Mo is provided between magnetic material layers. 
     
     
       7. The device of  claim 1 , wherein the second nonmagnetic layer is an oxide. 
     
     
       8. The device of  claim 6 , wherein the first magnetic layer comprises a plurality of the middle layers. 
     
     
       9. The device of  claim 1 , further comprising a first layer on the second nonmagnetic layer, which is opposite the first magnetic layer. 
     
     
       10. The device of  claim 9 , further comprising a first electrode, and a second electrode provided on the second magnetic layer, wherein
 the first layer is provided on the first electrode. 
 
     
     
       11. The device of  claim 9 , wherein the first layer includes at least one element selected from the group consisting of Al, Be, Mg, Ca, Sr, Ba, Sc, Y, La, Si, Zr, Hf, W, Cr, Mo, Nb, Ti, Ta, and V, or a boride of these elements. 
     
     
       12. A magnetoresistive memory device comprising:
 a first magnetic layer having a variable magnetization direction, the first magnetic layer including Mo or W; 
 a first nonmagnetic layer provided on the first magnetic layer; 
 a second magnetic layer provided on the first nonmagnetic layer, a magnetization direction of the second magnetic layer being invariable; and 
 a second nonmagnetic layer of a nitrogen compound provided on the first magnetic layer, which is opposite the first nonmagnetic layer. 
 
     
     
       13. The device of  claim 12 , wherein:
 the first magnetic layer is a storage layer having magnetic anisotropy perpendicular to a film surface; 
 the second magnetic layer is a reference layer having magnetic anisotropy perpendicular to a film surface; and 
 the first nonmagnetic layer is a tunnel barrier layer through which a tunneling current flows. 
 
     
     
       14. The device of  claim 12 , wherein the first magnetic layer includes Fe or Co. 
     
     
       15. The device of  claim 12 , wherein the first magnetic layer has a stacked layer structure in which a middle layer including Mo or W is provided between magnetic material layers. 
     
     
       16. A magnetoresistive memory device comprising:
 a first magnetic layer having a variable magnetization direction; 
 a first nonmagnetic layer provided on the first magnetic layer; 
 a second magnetic layer provided on the first nonmagnetic layer, a magnetization direction of the second magnetic layer being invariable; 
 a second nonmagnetic layer provided on the first magnetic layer, which is opposite the first nonmagnetic layer; and 
 a first layer comprising a magnetic material and a nonmagnetic material, the first layer provided on the second nonmagnetic layer, which is opposite the first magnetic layer. 
 
     
     
       17. The device of  claim 16 , wherein the first nonmagnetic layer comprises MgO, and the second nonmagnetic layer comprises MgO. 
     
     
       18. The device of  claim 16 , wherein the first magnetic layer has a stacked layer structure in which a middle layer including Mo or W is provided between magnetic material layers. 
     
     
       19. The device of  claim 16 , wherein the first layer includes Co or Fe as the magnetic material and W or Mo as the nonmagnetic material, and the first layer is amorphous. 
     
     
       20. The device of  claim 16 , further comprising a second layer on the first layer, which is opposite the second nonmagnetic layer, wherein
 the second layer includes at least one element selected from the group consisting of Al, Be, Mg, Ca, Sr, Ba, Sc, Y, La, Si, Zr, Hf, W, Cr, Mo, Nb, Ti, Ta, and V, or a boride of these elements. 
 
     
     
       21. The device of  claim 16 , wherein:
 the first magnetic layer is a storage layer having magnetic anisotropy perpendicular to a film surface; 
 the second magnetic layer is a reference layer having magnetic anisotropy perpendicular to a film surface; and 
 the first nonmagnetic layer is a tunnel barrier layer through which a tunneling current flows.